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The human heart beats between 60 – 100 times every minute and around 2.5 billion times in an average lifetime! This feat is accomplished by a group of specialized cells in the heart that compose the ‘Cardiac conduction system’. The conduction system generates an ‘electrical impulse’ which conducts via a specialized network of cells and reaches the cardiac muscle thereby triggering a muscle contraction. This fascinating network of cells ensures synchronized contraction of all 4 chambers of the heart, beat after beat. Thus, for the heart to function normally, not only is an intact blood supply (normal blood vessels) essential but also an intact electrical system is mandatory!
Abnormalities of the conduction system can result in arrhythmias or abnormal rhythm which may manifest as either a slow heart rate (bradyarrhythmias) or a very rapid heart rate (tachyarrhythmias).
Bradyarrhythmias
Bradyarrhythmias, in general, occur in the elderly. Age-related changes in the conduction system can result in a slowing of the heart rate (bradycardia) or a block in the electrical conduction such that the impulse generated in the upper chamber fails to reach the lower 2 chambers of the heart (AV block). Patients usually present with brief periods of loss of consciousness lasting for a few seconds with spontaneous recovery. People may also present with episodes of giddiness or sudden blurring of vision or tiredness while walking. Since slowing of the heart rate is intermittent, symptoms are episodic and may be as frequent as several times in a day or as rare as once in a few months.
Undetected and untreated, the condition is often life-threatening with patients suffering from recurrent falls and its consequences like fractures and head injuries. Bradyarrhythmias are easily treated using a permanent pacemaker that is inserted under local anaesthesia just below the left or right collar bone beneath the skin. The pacemaker provides backup electrical impulses at a pre-specified rate of 60-70/min that ensures adequate muscle stimulation and contraction.
Tachyarrhythmias
Occasional missed beats or ectopics are normal and need no treatment. 1 in every 1000 individuals has additional conducting tissue in the heart that intermittently causes a form of short-circuiting with parts of the normal conduction system resulting in heart rates of 150-250 beats per minute or even faster. These abnormally rapid rhythms may originate in the upper chambers of the heart (supraventricular tachycardia) or from its lower chambers (ventricular tachycardia). Patients complain of abnormal or rapid heartbeats (palpitations) or may even complain of giddiness. Some patients may present with strokes (paralysis) because of the tendency of some of these arrhythmias to form blood clots within the heart. Although most common in adults these arrhythmias may also be encountered in children and the elderly. In general, supraventricular tachycardias cause recurrent symptoms but are rarely life-threatening.
Drugs can be used to control symptoms but need to be taken for a long time. Electrophysiological Study and Radiofrequency Ablation (EPS+RFA) is a one-time curative procedure wherein special catheters are passed through the groin and the abnormally conducting tissue is closed down using radiofrequency energy. The procedure is done under local anaesthesia and requires admission for a day or two. EPS+RFA for most supraventricular arrhythmias has a success rate of > 95% with a very low recurrence rate. Certain ventricular tachycardias can occur in patients with poor heart function (because of prior myocardial infarction) and tend to be life-threatening within minutes of onset. Many of these patients benefit from an Implantable cardioverter-defibrillator (ICD), a device akin to a pacemaker but with an additional function to terminate such life-threatening arrhythmias. Consult with the top cardiologist in Mangalore for the treatment procedures.
Some patients with very poor heart function suffer from another kind of conduction abnormality characterized by dyssynchronous contraction of the left and right ventricles. A Cardiac Resynchronization Therapy device is an advanced form of pacemaker that tries to synchronize contraction between the two ventricles thereby improving heart function by an additional 5% in such patients.
Rhythm disorders constitute a significant portion of cardiac abnormalities that are often underrepresented because of a general lack of awareness among the public. Electrophysiology is a distinct subspecialty of cardiology that deals with the management of arrhythmias and heart failure using pharmacotherapy, Electrophysiological studies, and Radiofrequency ablation techniques (EPS+RFA) or by implanting specialized devices. Visit the best cardiology hospital in Mangalore for treatment.
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